vfs_glusterfs: Fix a memory leak in connect path

vfs_glusterfs: Fix a memory leak in connect path

Early return in case of failure to set snapdir-entry-path xlator option
leaks talloced tmp_ctx.

Signed-off-by: Anoop C S <anoopcs@redhat.com>
Reviewed-by: Guenther Deschner <gd@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Autobuild-User(master): Günther Deschner <gd@samba.org>
Autobuild-Date(master): Fri Oct  7 19:39:11 CEST 2016 on sn-devel-144

Bug: https://bugzilla.samba.org/show_bug.cgi?id=12377

(cherry picked from commit 06281e8f1b912540a8cc2a79497b074dbe559d53)